C Program to Print Hourglass Pattern

The Hourglass Pattern is a symmetrical pattern similar to an hourglass shape. It can be visualized as an inverted full pyramid placed on a regular full pyramid. In this article, we will learn how to print the Hourglass Pattern using a C program.

Program to Print Hourglass Pattern in C

Star Pattern

#include <stdio.h>

int main() {
    int n = 5;

    // Outer loop to iterate through each row
    for (int i = 0; i < 2 * n - 1; i++) {
      
        // Determine the row level relative to the center
        int l = (i < n) ? i : 2 * n - 2 - i;

        // Print leading spaces
        for (int j = 0; j < l; j++) {
            printf(" ");
        }

        // Print stars in the current row
        for (int k = 0; k < 2 * (n - l) - 1; k++) {
            printf("*");
        }
        printf("\n");
    }

    return 0;
}

Number Pattern

#include <stdio.h>

int main() {
    int n = 5;

    // Outer loop to iterate through each row
    for (int i = 0; i < 2 * n - 1; i++) {
      
        // Determine the row level relative to the center
        int l = (i < n) ? i : 2 * n - 2 - i;

        // Print leading spaces
        for (int j = 0; j < l; j++) {
            printf("  ");
        }

        // Print numbers in the current row
        for (int k = 0; k < 2 * (n - l) - 1; k++) {
            printf("%d ", k + 1);
        }
        printf("\n");
    }

    return 0;
}

Alphabet Pattern

#include <stdio.h>

int main() {
    int n = 5;

    // Outer loop to iterate through each row
    for (int i = 0; i < 2 * n - 1; i++) {
      
        // Determine the row level relative to the center
        int l = (i < n) ? i : 2 * n - 2 - i;

        // Print leading spaces
        for (int j = 0; j < l; j++) {
            printf("  ");
        }

        // Print alphabets in the current row
        for (int k = 0; k < 2 * (n - l) - 1; k++) {
            printf("%c ", k + 'A');
        }
        printf("\n");
    }

    return 0;
}

Output

* * * * * * * * *   |   1 2 3 4 5 6 7 8 9   |   A B C D E F G H I
  * * * * * * *     |     1 2 3 4 5 6 7     |     A B C D E F G
    * * * * *       |       1 2 3 4 5       |       A B C D E
      * * *         |         1 2 3         |         A B C 
        *           |           1           |           A
      * * *         |         1 2 3         |         A B C
    * * * * *       |       1 2 3 4 5       |       A B C D E
  * * * * * * *     |     1 2 3 4 5 6 7     |     A B C D E F G
* * * * * * * * *   |   1 2 3 4 5 6 7 8 9   |   A B C D E F G H I

Explanation:

The outer loop runs for 2 * n - 1 iterations for printing each row of the pattern.
- For rows i < n, it processes the top half (inverted pyramid).
- For rows i >= n, it processes the bottom half (regular pyramid).
The l variable determines the relative position of the current row from the top or bottom center:
- Top half: l = i.
- Bottom half: l = 2 * n - 2 - i.
The first inner loop prints the number of leading spaces.
The second inner loop prints the stars (or numbers/alphabet).

C Program to Print Hourglass Pattern

Program to Print Hourglass Pattern in C

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